The adoption of innovative treatments for drug dependence will depend not only on the effectiveness, but also the cost-effectiveness of treatments. Much of community-based treatment is government funded. The government seeks cost accountability and value for expenditures. Further, programs are increasingly constrained to provide treatments that maintains their financially viability. Thus, there is increasing need to understand the costs as well as the effects of treatment. As the NIDA Clinical Trial Network (CTN) will conduct many large trials, it is a historic opportunity to conduct cost-effectiveness analyses (CEAs). We propose to conduct three CEAs of treatment for substance abuse. This will build on our previous research. We will analyze the: 1) CTN trial of Motivational Enhancement Therapy Interviewing (Dr. Carroll, P.I.), 2) CTN trial of Motivational Enhancement Therapy Intervention (Dr. Carroll, P.I.), and 3) the CTN trial of Motivational Incentives (Dr. Stitzer, P.I.). While there are well-known guidelines for CEA in general, there are important differences in applying CEA to drug treatment. At the culmination of our analyses, we will have findings on the cost-effectiveness of new therapies. These findings will be useful for policy decisions and will build a database of CEAs of treatment programs. We will also be able to provide guidelines for future CEAs of trials in the CTN. We are well poised to collaborate with the CTN. We have the collaboration and cooperation of the Lead Investigators of the trials. Dr. Sindelar is a co-investigator in the New England Node of the CTN and on the protocol development team for a CTN project assessing organizational aspects of the treatment programs. Further, we have received formal approval by the CTN Concept Review Committee and the New England Node. These are key steps in obtaining the collaboration of the researchers and the treatment programs. In addition, we have been working with a community treatment program in order to refine our questionnaires. Our consultants are pivotal investigators in CTN nodes. These collaborations and arrangements will ensure the successful achievement of our goals.